Generally, a door is installed at the front of furniture such as a wardrobe, a table, a storage closet or a bathroom cabinet to give fine appearance while the stored articles are prevented from being damaged without exposing the stored articles, and such a door is substantially classified as a swing type door or a sliding type door according to the opening scheme.
In case of the swing type door, one side of the door is hinge-coupled or provided with a hinge installed thereto, so that the door is opened and closed with a constant radius of rotation around the fixing point and corresponding to a width of the door. Thus, there must be secured a constant rotation radius necessary to open or close the door necessary to open or close the door.
In case of the sliding type door, doors overlap each other to be opened or the overlapped doors are spread on rails provided as many as the number of doors while the doors slide relatively to each other. Although the sliding type door is not required to secure a space corresponding to the rotation radius for rotating the doors differently from the swing type door described above, since the rails are exposed in state that the door is closed, the appearance is deteriorated. In addition, when foreign materials such as dust are heaped on the rails, the doors may not be smoothly operated.
In addition, in case of the sliding type door, due to the rails provided as many as the number of doors, the storage space of furniture may be reduced due to the width of the rails
To solve the above-described problems, a sliding type door has been disclosed in Korean Registered Patent No. 10-0987123 previously applied by and issued to the same applicant as the present invention, in which one door desired to be opened overlaps another door to be opened toward a front of the another door while the desired door is spaced apart forward from the another door by separation means provided to sliding means when the desired door slides on a rail installed to a top surface by the sliding means.
However, in the above-described registered patent, the door has a complex structure due to the sliding means and the separation means provided to the sliding means.
To solve the problems, a device for opening and closing a door, which is invented to improve the above-described patent, has been disclosed in Korean Registered Patent No. 10-1180469 issued to the same applicant as the present invention, in which the doors slide on a pair of rail frames having rail grooves, which are installed to the top and bottom surfaces of furniture while the doors overlap each other by an upper connection frame, a lower installation frame and forward and backward transporting means, so that the doors are opened or closed.
In addition, as disclosed in Korean Registered Patent No. 10-1087289, a sliding member is provided on a connection frame to move forward and backward while a door slides on a pair of rail frames having rail grooves, which are installed to the top and bottom surfaces of furniture, so that the door is opened or closed.
However, the door disclosed in the registered patents essentially includes the forward and backward transporting means or the sliding member which moves forward and backward while the door slides, and the forward and backward transporting means or the sliding member has also a very complex structure, so that the assembly work is cumbersome and inconvenient.